What’s At Stake In New Hampshire’s Republican Primary

John Kasich, left, and Donald Trump, right, speak with members of the media after the Republican presidential primary debate hosted by ABC News at St. Anselm College on Saturday in Manchester, New Hampshire.

Matt Rourke / AP

MANCHESTER, N.H. — Before the Iowa Republican caucuses last week, we warned you that the uncertainty in the race was high and that the polls might be way off. That’s even more true here in New Hampshire.

At least we know that Donald Trump will finish first on the Republican side? Well, probably. Trump has led all but one poll here since July; his numbers have slumped by a couple of percentage points since his second-place finish in Iowa, but nobody has come especially close to him. And yet, because the uncertainty is so great in New Hampshire, Trump’s victory is not quite assured: Our polls-plus forecast still gives Trump a 31 percent chance of somehow losing here.

The reason for this is that, historically, the more viable1 candidates there are in a state, the more error-prone the polling has tended to be. Multi-candidate races open up the possibility of last-minute tactical voting and otherwise give voters plenty of options, making them more likely to change their minds at the last minute. Our forecast models account for this dynamic, which is why Trump’s lead is much less safe than Bernie Sanders’s in the two-way race on the Democratic side, even though both candidates lead their nearest competitor by about the same 15-percentage-point margin in the polling average. (I think the model might be a little bit too confident about Sanders — I’d personally put his odds at more like 95 percent rather than 99 percent — but we’ll save that discussion for later.)

So let’s look at New Hampshire from the standpoint of the six leading Republican candidates. For each one, I’ve listed their 90th percentile and 10th percentile forecasts from our polls-plus model to show the most likely range of possible outcomes.2

It’s entirely possible; the polls-plus model projects Trump to finish with 27 percent of the vote — a little less than the 30 percent he has in the polling average. But there’s a huge amount of uncertainty around that estimate. Suppose, for instance, that Trump finishes with a vote share in the mid-to-high 30s. Such a performance would erase many of our doubts about Trump’s ceiling and make him look formidable in South Carolina and beyond.

Conversely, if Trump won but with more like the 27 percent of the vote that Pat Buchanan got in New Hampshire in 1996, he’d look more like a factional candidate who was benefiting from the divided field. And if Trump’s vote share falls into the low 20s or even the high teens, meanwhile, he would be vulnerable to losing New Hampshire outright. It would also raise a lot of questions about whether the polls were oversampling Trump voters.

Marco Rubio

90th percentile forecast: 25 percent

10th percentile forecast: 9 percent

The polls-plus forecast still has Rubio in second place, but that’s deceptive. He’s only a fraction of a percentage point ahead of John Kasich, with Jeb Bush and Ted Cruz lurking almost as close. In fact, the polls-plus forecast has Rubio with a 64 percent chance of finishing third or worse and he could easily enough slip to fifth or sixth. Here’s our final matrix of probabilities for Rubio and the other candidates:

CANDIDATE

FIRST

SECOND

THIRD

FOURTH

FIFTH

SIXTH+

Donald Trump

69%

19%

7%

3%

1%

<1%

Marco Rubio

11

25

23

19

13

9

John Kasich

10

24

23

19

14

11

Jeb Bush

6

16

20

22

19

17

Ted Cruz

4

13

17

22

22

23

Chris Christie

<1

2

5

10

18

64

Carly Fiorina

<1

<1

3

5

11

80

Ben Carson

<1

<1

<1

<1

3

96

Chance of finishing in each position, N.H. GOP primary

Percentages displayed are from FiveThirtyEight’s polls-PLUS forecast.

I’m erring toward the pessimistic interpretation for Rubio because I’m not sure that polls have had time to fully capture the impact of his poorly-reviewed debate performance from Saturday. At the same time, pundits are often pretty bad at anticipating how voters will react to debates and other gaffes. Ultimately, the impact of the debate will be hard to measure: Rubio could wind up with 18 percent of the vote despite the debate, but would have gotten 22 percent without it.

No matter what happens, the media reaction to Rubio’s finish tonight is likely to be hyperbolic. If he gets (say) 22 percent of the vote, or only 8 percent, a strong reaction might be warranted. But you may also see reporters parsing relatively small differences, like between 16 percent and 13 percent. Mostly, you should ignore them, because there are two more important things to watch in the aftermath of New Hampshire. The first, as FiveThirtyEight contributor Julia Azari writes, is how Republican Party leaders react to Rubio’s performance. Is he continuing to get endorsements? How are people who actually have influence within the Republican Party — not just TV talking heads — spinning his performance? If Rubio finishes narrowly ahead of Bush, are there calls for Bush to drop out? The second thing to watch: How does Rubio perform in this Saturday’s debate in South Carolina.

John Kasich

90th percentile forecast: 24 percent

10th percentile forecast: 8 percent

As I said on our podcast, I suppose I’ll be “that guy” who thinks Kasich has some potential to outperform his polls. As measured by his number of voter contacts (as well as our own observations), he has one of the best ground games in New Hampshire. Also — this was a favorable indicator for Cruz and Rubio before Iowa — he’s seen a late, Election Day spike in Google search traffic. The polls-plus model also has Kasich beating his polls by a couple of percentage points, for what it’s worth. We’ll know soon enough.

My guess is that there’s a difference between Kasich doing pretty well and doing really well. If Kasich replicates Jon Huntsman’s 17 percent of the vote from four years ago, he might be a good story for a few days but not have much impact beyond that. If he gets to 20 percent or more of the vote, however, finishing well ahead of the other “establishment lane” candidates and even threatening to win here, that’s a different story.

Jeb Bush

90th percentile forecast: 22 percent

10th percentile forecast: 7 percent

Bush is only barely behind Kasich in the New Hampshire polls, and has some advantages Kasich does not: more money, more organization and more support from party elites. That could leave Bush better poised than Kasich to take advantage of a strong finish here.

He also has one big problem, however: Bush is much more of a known commodity among Republican voters, and he’s not very well-liked, with favorability ratings barely better than breakeven within his own party. So one possibility is that Bush has a strong performance in New Hampshire and eventually, after some further reshuffling, becomes the “establishment lane” finalist after all — only to lose to Trump or Cruz.

Ted Cruz

90th percentile forecast: 20 percent

10th percentile forecast: 6 percent

Cruz, who didn’t get much of a bounce after Iowa, probably has the least on the line in New Hampshire. If he does well here, that will be a sign that his turnout operation is effective at identifying evangelical and “movement conservative” voters even in a state that has relatively few of them. It might also mean he’s picked up some support from Rand Paul, who was reasonably popular here and dropped out of the race after Iowa.

But Cruz should mostly be focused on South Carolina and the March 1 primaries, where he’ll need to rack up a lot of delegates to make up for a calendar that will turn worse for him as the election wears on. Both Cruz and Trump would benefit from an ambiguous outcome in which at least three of Rubio, Kasich, Bush and Christie continue to run for some time after New Hampshire.

Chris Christie

90th percentile forecast: 13 percent

10th percentile forecast: 3 percent

I’ve been a little surprised that Christie, who has been excellent in debates and in the retail settings where we’ve seen him here in New Hampshire, is stuck at just 6 percent in the polls. When I mentioned this on Twitter yesterday, there were a bunch of theories: Bridgegate, The Hug, and even Christie’s being a New York Mets fan. I get all that, and we were pretty skeptical about Christie’s chances a year or so ago when other people were more bullish on them. But we’re not talking about Christie winning the nomination; we’re talking about him failing to poll in the double-digits in a state that should be pretty good for him.

Still, there’s some chance Christie could overperform his projection, especially if the Republican debate is not fully priced into the polls. The polls-plus model gives Christie a 7 percent chance of finishing in the top three, an outcome that would have the benefit of being unexpected and would therefore get him a lot of buzz. And if Christie finishes ahead of Rubio, the media buzzards will be circling Rubio’s campaign.

Footnotes

Jim Gilmore won’t contribute much to the uncertainty in New Hampshire by having his name on the ballot and getting his 0.2 percent of the vote, but candidates who are polling in the double-digits or higher certainly do.